Interlocking system for railroads



0d 8, l940 s. J. MAcKEY INTERLOCKING SYSTEM FOR RAILROADS Filed June 22, 1937' 2 Sheets-Sheet 1 1 2 W 5 I 9 O n. |I| 2| A. .f5 Ml: h 52: IIII|II|.I|" .fg if w O l Wu emv f 4 5 R VIII IIIL I n 5 I 8 H M w+, 4 O H G C l u.. 4,--. I 5 .H7 2 1H 4 Int G y 7 A.

E 6, 'Il I c JA 11 9 nu. e 2 7 l I IEI I 4III F H w A 2H n l 4 n 2 I .o G o III II. 4 v 2 RGN- 6 O #i501 le Ve, VII... IIIIIIIIIIIIII IIL V I|..

I I I I Y I FIG.. 3.

i 15o I I Oct. 8, 1940. s J. MACKEY IN'IVERLQCKING SYSTEM FOR RAILROADS Filed June 22, 1937 2 Sheets-Sheet 2 .III'IIIIIIIIIIIIIIIIIIIIIIIII ATTOR N EY Patented Oct. 8, 1940 l? STATES INTERLOCKING SYSTEM FOR RAILROADS Stuart J. Mackey, Rochester, N. Y., assigner to General Railway Signal Company, Rochester,

Application .lune 22, 1937, Serial No. 149,700

2() Claims.

This invention relates to electric interlocking systems for railroads, and more particularly pertains to an interlocking system of the entranceexit type.

An interlocking system usually involves a number oi 'track switches and Crossovers interconnecting several tracks with suitable signals for governing traino over the various routesformed by the switches and Crossovers. The present invention contemplates that the track layout of the interlocking plant be represented by a miniature track diagram located in a central office, which track diagram corresponds to the actual layout in the field. The miniature track diagram is suitably mounted to form a part of the control machine and has located thereon initiating and completing buttons or levers or the control of traffic through the interlocking plant. The operation oi an initiating button at the entrance to a route together with the actuation of the completion button for the exit end of that route compositely controls all of the individual track switches included in that route and clears the signal for such route when all of the track switches have properly responded.

One of the objects of the present invention is to provide an interlock between the entrance and exit buttons in such a way that only one route from a group of conflicting routes may be established at any one time.

Another' object of the present invention is to provide that the route control which is manually conditioned to set up a route, shall be subject to automatic release upon the departing of a train from such route rather than upon the entrance of such train to the route as is the usual practice.

Another object of the present invention is to provide self-restoring entrance and exit buttons in such a way that the failure of a route to be completely manually conditioned, will result in the restoration of all those buttons manually operated in connection with the proposed route.

Another object of the present invention is to provide a novel interlock between the entrance and exit buttons so that the sequence of operation of the buttons for a particular route eiiects the control of the direction in which traliic is to be set up in that route.

Another object oi the present invention is to provide a novel control by the entrance-exit buttons in such a way that the initiating and completing for any given route end may be accomplished by a single button.

Gther objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in 'which like letters in the reference characters designate similar functions or relationships With the distinctiveness between such reference characters provided by the use of distinctive preceding numerals; in which like preceding numerals in the reference characters when applied to different letters represent the inclusion of such devices Within a particular group; and in which:

Figs. 1A and 1B, when placed side by side, diagrammatically illustrate the control oice and ield station apparatus included Within an interlocking system of the present invention as applied to a single crossover;

Fig. 2 illustrates diagrammatically a modified form of an entrance-exit control button; and

Fig. 3 illustrates diagrammatically a modified form of entrance-exit control to providev that directional control shall be established by sequential operation of the entrance-exit buttons instead of by distinctive operations for the initiating and completing manual acts on such buttons.

For the purpose of simplifying the illustration and facilitating in the explanation thereof, the conventional parts and circuits constituting the embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed, thedrawings having been made more with the idea of making clear the purposes and principles of the invention together with its mode of operation, than with the idea of illustrating the specific construction and arrangement of parts that would probably be employed in practice.

The various relays and their contacts are illustrated in a conventional manner and symbols are employed to indicate connections tothe terminals of batteries or other suitable sources of electric current supply instead of showing all of the wiring connections to such terminals.

The symbols (-1-) and are employed to indicate the positive and negative terminals respectively of suitable batteries or other sources of electric energy; and the terminals with rwhich these symbols are used are presumed to have current flowing from the positive terminal designated (-1-) to the negative terminal designated i The symbols (B+) and (B) indicate connections to the opposite terminals of a suitable battery, or other direct current source which has a center or intermediate tap designated (CN); and the circuits with which these circuits are used, may have current flowing in one direction or the other depending upon the par- 'ticular terminal used in combination with the intermediate tap (CN).

The symbols employed with any one circuit are considered to designate the terminals of the same battery or'other suitable source, but it is to be understood that as many separate sources may be provided as found necessary, or as many sources may be combined into a single source as found expedient in the practice of the invention. If alternating current is employed, then the symbols should be considered to represent the instantaneous relative polarities of the respective terminals.

Where groups of devices are referred to in a general way, such devices will be designated by the letters or preceding numerals characteristic of such groups instead of mentioning each specic reference character of such groups.

APPARATUS Track'Zayout.-In Fig. 1B of the accompanyingv points TSA and TSB. The stretch of double track includes a main line extending from signal 2 to signal 4, and another main line extending from a signal 3 to a signal 5. Signals 2 and 5 govern the traflic over the crossover as well as over the main line tracks with which they are associated. f

Inasmuch as the opposite ends of a crossover are usually operated at the same time, the crossover may be considered as operated by a single switch machine SM, which may be of any suitable type, such for example, as disclosed in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. However, two switch machines SM may be employed for the respective track switches, if desired, all within the scope of the present invention.

It should also be understood that the invention is not limited, as thus shown, to the control of a crossover and signals of this chosen layout, but may be extended for any desired number of switches and signals and may be readily applied to all types of track layouts found in interlocking plants. The manner in which the present invention applies to a single track switch instead of a. crossover will be pointed out hereinafter by mentioning those parts of the present disclosure which may be readily omitted when only a single turnout switch is controlled by a system constructed in accordance with the present invention.

The signals 2, 3, 4 and E'are assumed to be color light signals giving the usual indications of green for clear and red for danger or stop, and

yellow, ii an'added indication is desired, for caution. However, these signals may be of the search light type, the semaphore type, or any suitable type instead of the particular type chosen for the embodiment of `the present invention.

The track layout has been shown as divided into twol track circuits 6 and 'l by suitable insulated joints, which track circuits are provided with the usual track batteries and track relays of which trackl relays'BT and 1T have been shown.

These normally energized track circuits are wired in the usual manner to provide for' fouling protection and to provide for the insulation of the track switches, such details of wiring having been omitted for the sake of simplicity in the disclosure. Slow acting track repeating relays STP and 'ETP are respectively associated with the track relays 6T and 1T.

The crossover, including the track switches TSA and TSB, is provided with the usual switch position repeating relay WP of the usual polarneutral type. This relay WP is energized with one polarity or the other in accordance with the normal or reverse locked position of its track switches in correspondence with its switch machine SM, and is deenergized whenever its track' switches (or crossover) are unlocked or are in operation. The polarized circuit for controlling such a switch position relay is governed through the medium of a point detector contact mechanism, such as. shown, for example, in the patent to C. S. Bushnell, Patent No. 1,517,236 dated November 25, 1924, it being understood, of course, that there would be two such mechanisms if two switch machines SM were employed for the crossover, which mechanisms would jointly control the polarized circuit for the single switch position repeating relay WP for such crossover.

Associated with the switch position repeating relay WP are correspondence relays NCR and RCR. These correspondence relays may be controlled in any suitable way so as to indicate when the track switches (or crossover) are in correspondence with their control, but this has been specically shown in the present disclosure by controlling the correspondence relays through contacts on the relay WP and contacts of the switch machine control relays WNA, WR and WNB. These switch machine control relays WNA, WR and WNB are governed from the central olice, as shown in detail in the prior patent of A. Langdon, Patent No. 2,121,803, dated June 28, 1938, but no claim is to be made in this application to such subject matter shown in this prior patent. With the operation of these switch machine control'relays, as disclosed in the above mentioned prior application, the correspondence relays NCR and RCR are controlled in such a manner that the relays NCR and RCR are respectively energized when the track switches TSA and TSB are in correspondence with their normal or reverse controls, but these relays are always deenergized when there is a lack of correspondence. The correspondence indicated by these relays NCR and RCR is of the indirect type. For example, when the track switches TSA and TSB are in normal positions, the relay NCR is energized irrespective of whether a normal control is present or not, but the presence of a reverse control immediately deenergizes such relay NCR. Similarly, when the track switches TSA and TSB are in reverse positions, the relay RCR is energized irrespective of whether there is a reverse control present or not, but the presence of a normal control immediately deenergizes this relay RCR.

Associated with the switch machine control is a lock relay L which may be controlled as shown and described in the above mentioned patent of A. Langdon No. 2,121,803, dated June 28, 1938, it being considered sufficient for an understanding of the present invention to know that the lock relay L is normally energized, but is initially deenergized only when a switch machine control is presentl and the track switchesv are in correspondenoe therewith, and is maintained deenergized by the clearing of a signal over the crossover and also is maintained deenergized by the presence of a train on the associated track sections 6 and l.

Control machine. A control machine is located in the central office, and is provided with a control panel on which is located a track diagram corresponding to the actual layout in the eld. The crossover in the eld is represented by a miniature crossover ts which may have mov'- able miniature switch points operated by electromagnetic means, or may have its positions indicated by electric indicator lamps, or the like.

The control panel also includes an entranceexit button N`X for each of the signal locations, such as entrance-exit buttons 2NX, SNX, liNX and ENX for the respective signals 2, 3, i and 5. Associated with each of the entrance-exit buttons are suitable self-restoring stop buttons S, such as stop buttons 2S, 3S, S and 5S for respectively returning their signals to stop.

It is to be understood that the ends of the routes may or may not correspond to the location of the signals as represented by the entranceexit buttons NX on the track diagram, as a route is usually considered to extend from one signal to the next signal governing traiiic in the saine direction or to some arbitrarily chosen point.

Each entrance button NX is in the form of a knob which is rotatable from a normal position to an operated position in both directions, and is self-restoring to its normal position from each of its operated positions. These buttons are preierably rotatable in directions symbolizing the direction of traic movement over the routes which they control. For example, a button which is to set up east bound traine is preferably rotated in a clockwise direction to an operated position; while a button which is to establish west bound traffic is preferably rotated in a. counterclockwise direction to an operated position.

The entrance-exit buttons NX may have associated therewith suitable indicator lamps to advise the operator when the associated signal is clear, but such indicators and their control have been omitted from the present disclosure for the sake of simplicity, the control of such indicators having been shown in detail in the prior application of S. N. Wight, Ser. No. 69,905, iiled March 20, 1936.

The track diagram also preferably includes track indicators for advising the operator when the individual track sections or track circuits are occupied by trains, but such control and indicators have been omitted for the sake of simplicity, reference being made to the above mentioned S. N. Wight application, Ser. No. 69,995, for such details.

Although the present invention is not particularly concerned with the emergency control of the track switches, it is to be understood that an emergency switch control lever SML (not shown) is also provided and may enter into the control of the switch machine SM in a manner set out in detail in the above mentioned prior patent of A. Langdon No. 2,121,803, dated June 23, 1938.

Route relays-The control oice equipment also includes a route relay for each of the routes over the track layout. These route relays are selectively controlled by the entrance-exit buttons NX and by slow release repeater relays R, as will be pointed out more in detail hereinafter. The route relays 2 4, 2 5 and 3 5 control traffic between the signals represented by the numbers in the reference characters of such route relays.

The route relays provide for the positioning of the track switches TSA and TSB through the control of switch machine SM in a manner as speciiically disclosed in the above mentioned patent of A. Langdon No. 2,121,803, dated June 28, 1938.

The route relays 2 4, 2 5 and 3 5 also control the clearing of the signals through suitable circuit selections for the respective signals as will be pointed out in detail hereinafter.

In an interlocking system, there is usually suitable approach locking and route locking associated with the signals and route controls and this disclosure considers the application of any suitable locking in the system of the present invention, all of which locking may be applied in the usual way.

It is believed that the remaining features of the present invention will be best understood by considering the detailed operation of the system.

OPERATION Normal conditions.-Although the track switches TSA and TSB are usually left in their last operated positions, they have been shown in positions -lor the passage of the main line trarc. The signals are of course normally at stop with the lower or red indicator of each signal normally illuminated, unless approach lighting features are employed in accordance with the usual practices.

With the track sections 6 and 'l unoccupied, the track relays 6T and 1T are of course normally picked up.

The lock relay L is normally energized, while either the correspondence relay NCR or RCR energized depending upon the last position of the track switch.

All of the route relays in the central office and the indicators on the control panel are normally deenergized to provide what has been conveniently termed a normally dark board.

Establishing a route-When the operator desires to set up a route from the signal 2 to the signal 0, for example, he rotates the entranceexit button 2NX in a clockwise direction to its operated position, in which position he holds the entrance-exit button QNX until the slow acting repeater relay 2R is picked up by a circuit closed from through a circuit including windings of relay 2R, lever contact 20 in an operated position, to

After the operator actuates the entrance-exit button ZNX, he then glances along the miniature trackway and nds that there are no route lock lamps indicating a conflicting route, so that he actuates the entrance-exit button 4NX by rotating it in a clockwise direction to its operated position. The relay 2R is suiiiciently slow acting so as to remain picked up for a period of time allowing the operator sufficient time to scan the contemplated route and to operate the entranceexit button LENX, as well as for the picking up of the associated route relay.

In this case, the route relay 2 4 is energized during the release of relay 2R by a circuit closed from through a circuit including back con-l CFI mediately actuates the polar contacts of route relay 2 4 to a right hand position so that positive energy (-1-) is supplied to the heel of contact 2| through polar contact 26 to continue the energization of its pick up circuit, although the neutral conta-cts of the relay 2 4 open during the picking up of the relay. The picking up of the contacts of the relay 2 4 closes a stick circuit for this route relay from (B+), through a circuit including polar contact 2 in a right hand position, front contact 28, lower winding of route relay 2 4, front contact 29 of stop button 2S,

front `contact Si] of stop button 4S, wire 3l, front contact 32 of track repeater relay BTP, to (CN).

The current which ows in this stick circuit maintains the route relay 2 4 energized although after a short time the relay 2R drops away and opens the pick up circuit for the route 'relay` The release of the button 4NX causes it to restore to a normal position and also open the pick up circuit.

- Each of the remaining route relays 2 5 and 3 5 are picked up in a similar manner and are maintain-ed energized by their stick circuits which are wholly dependent upon their associated stop buttons S and traicrconditions for their respective routes. The interlock between the route relays will be discussed in detail hereinafter.

The picking up of the route relay 2 4 closes its front contact 33 and causes the normal operation of the switch machine SM to thereby position the track switches TSA and TSB in normal positions for main line traiiic which is indicated by the relay NCR picked up. As soon as the track switches are in correspondence with the switch control established by the route relay 2 4, the

relay L drops away which closes an energizing circuit for clearing the signal 2 from (-i) through a circuit including back contact 34v of relay L, front contact 35 of relay NCR, wire 33, front contact 3l of relay 2 4, polar contact 38 of relay 2 4 in a right hand position, to the signal 2. The clearing of the signal 2 conditions the route for the passage of traic.

When a train accepts the signal 2 and enters upon the track circuit 5, the track relay 6T is deenergized which in turn deenergizes the repeating relay @TP by the opening of contact 39. Before the track repeater relay ETP drops away opening front contact 32, the back contact 48 of relay T closes and supplies energy from (CN) to the wire 3l for maintaining the route relay 2 4 picked up.

The entrance of the train onto the track section and the resulting deenergization of the track relay 5T may put the signal 2 to stop in any of the usual ways, and the signal may also be made astick signal, if so desired, but for the purpose of the present disclosure such control has not been shown in detail. As the train passes through the train section, the route relay 2 4 remains icked up by reason of its stick circuit, but upon the departure of the train from the track circuit 6, the track relay 5T picks up before its repeater STP can pick up so that the contact 4l) is opened before the contact 32 closes. This sequence of operation causes a momentary opening of the stick circuit for theroute relay 2 4 resulting in its drop away. f

Throughout the time that the track circuit 6 is occupied, the lock relay L is maintained deenergized preventing Vcontrol of the switch machine SM by a conflicting route relay by reason of open contact l 9.

If a train for some reason failed to accept the signal 2 at clear, or the operator desired to stop the train after-having cleared the signal, all that is necessary to restore the signal 2 to stop conditions is for the operator to momentarily depress the stop button 2S which opens front contact 29 momentarily deenergizing the route relay 2 4 and causing it to drop way. `This in turn causes the signal 2 to be returned to stop.

Assuming that the route pointedl out above has been returned to stop either by manual orautomatic control, the route from the signal 2 to the signal 5 will be pointed out so as to show the manner in which the route relay 2 5 is maintained picked up while a train passes through two successive track circuits.

The operator successively actuates the buttons ZNX and 5NX which closes a pick up circuit for the route relay 2 5, from (-1-), through a circuit including back contact lll of relay 2 5, front contact 42 of relay 2R, back contact 43 of relay 2 4, upper winding of relay 2 5, back contact 44 of relay 3 5, back contact 45 of relay 5R, lever contact 45 in a right hand operated position, to This initial pick up `circuit actuates the polar contact 4l to a right hand position which applies energy to the heel of contact 4l.

As soon as the relay 2 5 picks up, a stick circuit is closed from (B+), through a circuit including polar contact 48 in a right hand position, front contact 49 of relay 2 5, lower windings oi relay 2 5, front contact 5t of stop button 2S, front contact 5l of stop button 5S, wire 52, front contact 53 of relay ETP, front contact 54 of relay 7T?, to (CN).

The closure of front contact 55 of relay 2 5 causes the control of the switch machine SM in a manner as pointed out in the above mentioned application of A. Langdon, Ser. No. 91,932, to cause the track switches TSA and TSB to assume reverse positions, after which the signal 2 is cleared by a circuit closed, from through a circuit including back contact 34 of relay L, front contact 56 of relay RCR, wire 5l, front contact 58 of route relay 2 5, polar contact 5S of relay 2 5 in a right hand position, to the signal 2, thereby causing it to be cleared.

When a train accepts such signal 2 for the crossover route, the track relay 3T is deenergized closingback contact E@ before the front contact 53 of relay TP opens. As the train continues over the route and enters they track circuit l, the back contact @l of track relay 7T is also closed. Both of these contacts 5o and 5l apply energy from (CN) to the wire 52 to maintain route relay 2 5 energized, although both of the track repeater relays @TP and 'ETP are now deenergized opening their respective contacts 53 and 54. As the rear of the train leaves the track circuit 6 rst in passing through the route, the track relay 6T picks up openinor back contact 5t and closing front contact 53, but the contact 6l is still closed so that the route relay 2 5 remains picked up. However, it will be readily apparent that as the train leaves the track circuit "l, the relays 'lT and ITP will pick up successively so that contact 6l opens before the contact 54 closes thereby momentarily deenergizing the route relay 2 5 upon the departure of the train from the route which such relay controls.

If the operator desires to reverse a particular route, he must rst put such route to stop. For example, if 'the train had not yet accepted the crossover route, above pointed out, then the operator desiring to reverse the direction over such route, would rst have to depress the stop button 2S deenergizing the route relay 2 5, so that the successive operations of the buttons 5NX and ZNX in counterclockwise directions canv energize the pick up circuit for the relay 2 5 for the west bound direction.

The operation of the button 5NX in a counterclockwise direction energizes the repeating relay 5R through an obvious circuit including the lever contact 46 in an operated position. The closure of front contact followed by the operation of button ZNX completes an initial pick up circuit for the route relay 2 5 from (-1-) through a circuit including back contact 62, front contact 45 of relay 5R, back contact 44 of relay 3 5, upper winding of relay 2 5, back contact 43 of relay 2 4, back contact 42 of relay 2R, lever contact 53 of button 2NX in an operated position, to The polar contact 4l immediately responds assuming a left hand position to apply energy to this pick up circuit although the back contact 52 of the relay 2 5 opens'. From this it will be readily apparent that if the relay 2 5 were maintained picked up by its stick circuit for a route from the signal 2 to the signal 5, that the picking up of the relay 5R could not apply energy from (-1-), to the initial pick up circuit by reason of the open condition of back contact 62 and polar contact 4l in a right hand position.

It will also be apparent that when a route is established over the main line between signals 2 and 4, that a coniicting route can not be established between the signals 5 and 2 because of the open back contact 43 on route relay 2 4, while a parallel on non-conflicting route can be established at any time.

For example, let up assume that the operator actuates the buttons 3NX and 5NX in clockwise directions, the repeater relay 3R is energized by an obvious circuit through the operated lever contact 6d. An initial pick up circuit for the route relay 3 5 is closed from (-1-), through a circuit including back contact 65 of relay 3 5, front contact E5 of relay 3R, back contact Si of relay 2 5, upper winding of relay 3 5, back contact E8 of relay 5R, lever contact 59 of button 5NX in an operated position, to which flows in this circuit immediately causes the polar contact 'Ill to assume a right hand position for applying (-1-) to the heel of contact 65.

As soon as the route relay 3 5 picks up, a stick circuit `is closed from (B-1-), through a circuit including polar contact 'Il in a right hand position, front contact l2 of relay 3 5, lower winding of relay 3 5, front contact 73 of stop button 3S, front contact 75 of stop button 5S, wire 15, front contact of relay 15 of relay l'TP, to (CN).

Thus, it is apparent that the route relay 3 5 may be picked up, although a route is established between the signals 2 and 4. This is because the initial pick up circuit for the route relay 3 5 does not include any interlocking contacts on the route relay 2 4. However, when a route is established between the signals 2 and 5 with the route relay 2 5 pick up, it is apparent that the route relay 2 4 cannot be picked up because of open back contact 23, and similarly, the route relay 3 5 cannot be picked because of open back Contact 6l. In a similar manner, when either or both of the route relays 2 4 and 3 5 are picked up, the route relay 2 5 cannot be energized because of interlocking contacts 43 and 44.

The contact .18 of route relay 3 5 controls the switch machine SM to cause the track switches TSA and TSB to assume normal main line posi- The current tions after which a circuit is completed for clearing the signal 3, from (-1-), through a circuitincluding back contact 34 of relay L, front contact 35 of relay NCR, wire 36, front contact 19 of relay 3 5, polar contact 80 of relay 3 5 in a right hand position, to the signal 3 causing it to clear in the usual way.

It will be readily apparent that the sequential operation of the relays 1T and 'ITP as a train passes through this route causes the back contact 11 to close before the front contact 'I6 opens so that the train does not release the route relay 3 5 until it departs from the route, at which time it is accomplished by the sequential opening and closingofcontacts Tl and 16.

It will thus be understood from lthe above description that the route relays are so interlocked with each other as to prevent conflicting route relays from being picked up at the same time. Also, the route relays are so associated with the entrance-exit buttons that when a particular route relay has been once picked up it cannot be disturbed by the operation of the entranceexit buttons associated with such route relay, as that route relay is then wholly dependent upon the associated stop buttons and automatic traffic control for its maintaining energy. This has the advantage that, when a route is once set up, it is not erroneously put to stop by the operation of its governing route buttons at a later time. f

Another advantage of this system of interlock will be apparent upon the consideration of that case in which an operator might forget to restore an operating button NX to its proper position if it were not of the self-restoring type.

For example, let us assume that the operator desired to set up a route from the signal 2 to the signal 4 and operated the button 2NX to the right, which for the purposes of the assumed case is considered to be of the stay-Where-put type, and then actuated the button-4NX, but for some reason or other the route was not established, (as for example, because of defective apparatus, or because of the existence of a conflicting route not exempliiied by the simple track layout employed but readily identified in the above referred to application Ser. 69,905, wherein a failure to establish a route between B and J due to the existence of a conflicting route between A and J, could cause the attempt to establish a route between C and K to result in the undesired establishment of a route between B and K), and he immediately follows the operation by endeavoring to establish another route from signal 3 to the signal 5. Under such circumstances, with stay-where-put buttons NX, (-1-) energy would b-e supplied to the `left hand terminals of both of the relays 2 5 and 3 5 upon the operation of the button 5NX. There would then be a race between the two relays with no definite way of detei-mining which of the two relays should be picked But the present invention prevents such a condition because the positive energy is supplied to the left hand terminal of the relay 2 5 only for a limited time determined by the drop away period of the relay 2R, so that under the circumstances above considered, only the relay 3 5 would have energy applied to both sides of its upper winding. In` brief, then, the present invention provides self-restoring entrance-exit buttons together with a slow release relay for storing entrance or initiating conditions only temporarily, to thereby prevent the establishment of an erroneous route in the event that an entrance button has. been previously operated and forgotten.V4

Modiycction of Fig. 2 The circuit arrangement shown in Figs. lA and 1B is considered to lbe modied by having an entrance-exit button of vthe'type shown in Fig. 2 substituted for each of its entrance-exit buttons. This is to illustrate hcw a mechanically time retarded contact may be employed instead of the electrically retarded contacts oiY the slow acting relays R. More specically, the contact 222 directly connected to the button ENX is shown as replacing the contact 22 of .the relay' 2R in Fig; 1A. Each of the remaining contacts on the relay 2 4 have been given the same reference characters as in Fig. 1A because the circuits are exactly the same. The operation oi the entrance-exit button ZNX tothe right causes energy'to be stored in the springs lill) and #Qiandthe air to be removed from the chamber of cylinder H32 so that upon the release of the button lZNX, the button slowly returns to its normal position by reason of the force stored in the springs it@ and IGI, the time being prolonged by the slow intake of air through the intake vent 03. The `contact 222 is suitably connected to the time retarded lever, or dash pot arrangement, and cooperates with its right hand Xed contact 8| in a wiping manner so that it continues to make its contact in an operated position for a prolonged period of time although the lever 2NX and its asociated mechanical movement is slowly returningto normal. However, the contacts 222 are open while the lever ZNX is in a normal position.

The operation of the button ZNX in a counterclockwise direction causes the plunger mit to be withdrawn from the chamber I E32 so that the restoration of the button ZNX and the opening of contact 222 from'its left hand operated position is immediate upon the removal of the operators hand from the button.

Modification of Fig. 3. Instead of providing rotary entrance-exit buttons NX as in Fig. 1A, this modified form contemplates the buttons NX to be of the self-restoring push button type so that Athe same kind of operation is provided for both the initiating and completing manual acts. This figure also employs sequence between the operation of the initiating and completing button to determine the directional control. For example, let us assume that the operator momentarily actuates the Aentrance-emit button ZNX3 followed by .the actuation of the button tNX The closure of back contact 50, energizes the relay 2R3through an obvious circuit so that it picks up its contacts. Then upon the actuation of the button vdNX?, a circuit is closed for the relay 2 4, from (-i-), through a `circuit including front contact .5l oi relay 2R3, front contact H52 of button 2NX3, upper winding of relay 2 4, back contact 233 of route relay 2 5, back contact 53 of button `liNX3, to This energizes the route relay 2 4 so that it picks up its contacts and closes its stick circuit as pointed. out in connection with Fig. 1A.

If the reverse sequence in operation of the buttons 4NX3 and ZNX3 occurred, the opposite polarv ity is applied to the relay 2 4 so as to establish the opposite direction over the route which it co-ntrols.

For example, the actuation of the button 4NX3 energizes through back contact i543 the relay R3 byan obvious circuit. Then the actuation of the button 2NX3, closesy a circuit for the relay 2 2 from (-1-), through a circuit including iront contact l55 of relay GRS, front'contact 53 of relay liNXfL back contact 233 of route relay 2 5, upper winding of relay E back Contact 52 of button ENXS, to The current iiowing in this circuit causes the polar contacts of they relay 2 4 to operate to the leit and the neutral contacts to picked up so that the `stick circuit is energized from (B-).

Therefore, it is readily apparent that the sequence in the operation of the buttons ZNXS and IBNX3 determines the direction in which traiiicis established through a route. it is to be understood that the energy from the front contacts i and |55 ofthe relays ERS and @R3 may be selected through contacts on the routerelay 2 i in a similar manner as provided in Fig. 1A so that the operation of the buttons 2NX3 and QNXS, while a route is established, will not effect that route. However, a route may be put to stop by reason of its associated stop button S the same as shown in Fig. 1. It is to be understood that all of the remaining features and means disclosed in Figs. 1A and 1B also apply to Fig. 3.

Control ,for @single track switch. In the event that the track layout of an interlocked group includes only a single track switch, such as track switch TSA, the remainder of the track layout K shown in Fig. 1B is modied accordingly. In other words, the signal 3 and the track section 'i `are vof course absent, and the track section S is then arranged to include all of the track on the turnout up to the signal 5.

In the control oiiice, the miniature track diagram is accordingly modied omitting the entrance-exit button SNK and thestop button 3S. The route relay 3 5 is also eliminated from the interlocking circuits and all of its contacts removed from the circuits in which they are included in accordance with the principles of circuit work. The switch machine control as governed by the relay 3 5 is accordingly modied together with the indicators which it controls. It is believed that this simple statement for the control of a single track switch is adequate for an understanding of how the present invention is employed with a single track switch and is also adequate for a disclosure which will furnish the basis of claims covering the present invention applied to a single track switch.

Having thus described an interlocking system of the entrance-exit type as one specific embodiment of the present invention, it is to be understood that various modiiications, adaptations and alterations may be made to meet the requirements of practice without in any manner departing from the spirit or scope of the invention except as limited by the appended claims.

What I claim is:

1. In a control system for railway track layouts having a plurality of routes formed by the track switches and having signals for governing trafc over such routes in opposite directions; control buttons for the ends of the routes; route establishing electro-responsive means appertaining to each of said routes and energized by currents of distinctive character in response to the sequential operation of the control buttons for the opposite ends of its route so as to assume distinctive energized conditions depending upon such sequence; switch control means governed by an energized route establishing electro-responsive means, irrespective of its distinctively energized condition, for operating the track switches to set up the route associated with said route establishing electro-responsive means; and signal control means governed by an energized route establishing electro-responsive means to clear the signal for one direction or the other over the route set up in accordance with its distinctively energized condition.

2. In an interlocking system for a railway track layout having a plurality of routes with signals for governing traiiic in opposite directions over such routes; control buttons for the ends of said routes; route establishing means including route relays, one appertaining lto each of said routes and responsive to only the sequential operation of the control buttons for the ends of its route to set up that route, and each said route relays being distinctively Conditioned by the sequence of operation of such control buttons to clear the signal for the end of the route having its control button operated first.

3. In a control system for a railway track layout having a plurality of routes formed by the track switches and having signals for governing traiiic over such routes, self-restoring control buttons for the ends of said routes, route establishing means associated with each of said routes and responsive to the joint operation of only the control buttons for the ends of its route so as to be rendered effective, and so as to prevent the route establishing means for any conflicting route from being responsive to said control buttons, manually operable stop contacts one associated with each of said signals, switch and signal control means governed by each of said route establishing means for setting up the route and clearing the signal of the route corresponding to that route establishing means then rendered ef- Iective, and means for maintaining a route establishing means eective until a train has passed completely through said route, or the stop contact associated with the cleared signal has been actuated.

4. In a control system for an interlocking plant having track sections interconnected by track switches to form a plurality of diierent routes and having signals for governing traic in opposite directions over the different routes; a control panel; self-restoring control buttons on said control panel for the ends of said routes, each of said buttons assuming a diiierent condition when actuated to designate the entrance of a route than when actuated to designate the exit of such route; route establishing means for each route for controlling said track switches to set up such route and for clearing the signal at one end of such route in response to only the entrance actuation of a control button for said one end of that route and the exit actuation of the control button for the other end of that route, and for controlling said track switches to set up said route but for clearing said signal at said other end of said route in response to only the entrance actuation of the control button for said other end and the exit actuation for the control button for said one end; and track circuit controlled means maintaining a route establishing means effective although the control buttons cont-rolling its response are only temporarily actuated.

5. In a control system for an interlocking plant; a railway track layout having track sections interconnected by track switches to form a plurality of different routes and having signals for governing traic in opposite directions over the track sections; self-restoring control buttons for each or" the signal locations of said track layout, each of said control buttons assuming one condition when actuated to designate its signal f location as the entrance point to a route, and assuming a different condition when `actuated to designate its signal location as an exit point to a route; a route establishing means appertaining to each of the routes and rendered effective in response to the entrance actuation of a control but- -ton at one end of the route and the exit actuation of the control button at the opposite end of the route to operate the track switches to set up that route and to clear the signal at the end of the route corresponding `to the control button actuated to designate the entrance point of such route; means for maintaining the entrance actuation for each of said control buttons for a predetermined time, whereby the control buttons for the entrance and exit ends of a route can be operated sequentially in that order; and means for maintaining eiiective a route establishing means once rendered eii'ective until a train has passed through its associated route.

6. In a systemof the character descri-bed for a railway track layout having a portion of track with signals at the opposite ends of such portion for governing traffic in opposite directions and having at least one intervening track switch, a control machine having a control panel upon which a miniature track diagram'of said portion of track is located, self-restoring control buttons on said panel at the point-s on said diagram corresponding to the signal locations of the actual track layout, a slow release relay for directly repeating each of said control buttons, route establishing means associated with said track portion for controlling the track switch and. for clearing one or the other of said signals in response to an entrance actuation for the sign-al to be cleared and an exit lactuation for the leaving point of the route set up, means for giving an entrance actuation to a route establishing means only upon the release of a control button after its actuation, and means for giving an exit actuation only during the actuation of a control button, whereby said control buttons must be operated in sequence in order to actuate said route establishing means and to thereby actuate it distinctively to determine the direction of traiiic.

7. In an interlocking system for railroads, a railway track layout having track sections interconnected by track switches to form a plurality of different routes and having signals for governing traic in opposite directions over the track sections; self-restoring control buttons for each of the signal locations of the track layout, each of said control buttons assuming an entrance actuated condition when actuated to designate its signal location .as .the entrance point to a route but relatively slowly returning from such entrance actuated condition, and assuming an exit actuated condition when actuated to designate its signal location as an exit point to a route but relatively quickly returning from such exit actuated condition; a route establishing means appertaining to each of the routes and rendered effective in response to the entrance actuation of a control button for one end of its route and the exit actuation of the control button for the opposite end of such route to operate the track switches to set up that route and to clear the signal at the end of the route corresponding to the control button actuated to designa-te the entrance point of such route; means for maintaining effective a route establishing means, when once rendered effective, dependent upon traiiic conditions; whereby the control buttons for the entrance and exit ends of a route can be operated sequentially in that order for establishing a route although such buttons restore to their normal conditions after a time to render .the route establishing means Wholly dependent upon traiiic conditions.

8. In a system for controlling traiiic on railroads; .a track layout having a portion of track with signals at the opposite ends of such portion for governing traflic in opposite directions thereover Vand'having at least one intervening track switch; a control machine having a control panel; a self-restoring control button on said control panel for each of said signals; a slow release relay associated with each control button for directly repeating such control button; a route relay associated with said track portion for, when energized, controlling the track switch, and for clearing one or the other of said signals depending upon whether such route relay is energized in one direction or the other; circuit means for connecting energy of one polarity to one terminal of said route relay when one of said control buttons is actuated and for connecting the opposite polarity to said one terminal when such control button is released while its slow acting relay is picked up; circuit means for applying the opposite polarity to said other terminal of said route relay when said other control button is released while its associated slow acting relay is picked up; and stick circuit means for said route relay energized dependent upon trafiic conditions.

9. In a system for controlling traffic on railroads; a track layout having a portion of track with signals at ythe opposite ends of such portion for governing traffic in opposite directions thereover and having at least one intervening track switch; a control machine having a control panel;

Y a self-restoring control button on said control panel for each of said signals; a slow release relay associated with each control lbutton and picked up each time its said control button is actuated; a route relay associated with said -track porti-on for, when energized, controlling the track switch and for clearing one or the other of said signals depending upon whether such route relay is energized in one direction or the other; circuit means for connecting energy of one polarity to one terminal of said route relay when one of said control buttons is actuated and for connecting the opposite polarity to said one terminal when such control button is released while said slow acting relay is picked up; circuit means for applying energy of one polarity to the other terminal of said route relay when the other control butt'on is actuated and for applying the opposite polarity to said other terminal of v said route rel-ay when said other control button is released while its associated slow acting relay is picked up; stick circuit means for said route relay energized dependent upon traffic conditions; whereby said route relay is energized in one direction .or the other depending upon the 'sequence in which said control buttons are actuated providing the first button actuated is released when the second button is actuated; and means preventing said route relay, while it is energized by said stick circuit means, from being energized in a direction opposite to that direction which initiallyk caused it to be picked up.

10.l In a switch and signal control system for a track layout having track sections interconnected by track switches to form a plurality of routes some ofv which are coniiicting; signals for governing trafhc in opposite directions over said routes; control buttons for the ends of said routes, said control buttons being of the self-restoring push button type, and there being one for each of said signals; a slow release relay associated. with each of said control vbuttons and energized upon each operation of its control button; a route relay for each of said routes for controlling the track switches to set up its route and for clearing one or the other of said signals governing traiic over such rou-te depending upon whether such route relay is energized in one direction or the other; circuit means for energizing each route relay in one direction or the other depending upon the sequence in which the control buttons for the ends of its route are actuated, said circuit means including said slow acting relays for such control buttons, and said circuit means for said route r'elays being so arranged as to allow only one route relay from among the conflicting routes to be energized at Vthe same time; and means for maintaining energized a route relay once energized dependent upon the passage of trailc through its associated route.

11. In a switch and signal control system for a track layout having track sections interconnected by track switches to form a plurality of routes some of which are conflicting; signals for governing trafc in opposite directions over said route; control buttons for the ends of said routes, said control buttons being of the self-restoring push button type, and there being one for each of said signals; a slow release relay associated with each of said control buttons and energized upon each operation of its control button; a route relay for each of said routes for controlling the track switches to set up its route and for clearing a signal for one direction or the other depending upon whether such route relay is energized in one direction or the other; circuit means for energizing each route relay in one direction or the other depending upon the sequence in which the control buttons for the ends of its route are actuated, said circuit means including said slow acting relays for such control buttons, and said circuit means for said route rel-ays being so arranged as to allow only one route relay from among the conflicting routes to be energized at the same time; means for maintaining energized a route relay once energized dependent upon the passage of traic through its associated routes, whereby the energization of a route relay initially rendered effective by the control buttons for the ends of its associated route is maintained energized dependent upon trac conditions; and means for preventing the operation of those control buttons which picked up an energized route relay from energizing such route relay in the opposite direction if operated in the opposite sequence, said means being effective only so long as such route relay is picked up.

12. In a control system for an interlocking plant having track sections interconnected by track switches to form a plurality of diierent routes and having signals for governing tramo in opposite directions over the different routes; a control panel; self-restoring control buttons on said control panel for the ends of said routes, each of said buttons assuming a diiierent condition when actuated ,to designate the entrance .of a route than when actuated to designate the exit of such route; a route relay for each of said routes for control-ling said track switches to set up its route and for clearing the signal at one end or the other of such route depending upon the polarity with which such route relay is energized; means for energizing each route relay with one polarity in response to only the entrance actuation of a control button for one end of its route and eXit actuation of a control button for the opposite end of that route, said means also energizing said routerelay with the lopposite polarity upon said other vcontrol button and the 'exit actuation of said one control button;` means maintaining energized a route relay once initially energized, said means being dependent upon trahie conditions and maintaining such route relay although the governing control buttons restore to their normal conditions; and means controlled by each route relay for preventing said control buttons for the opposite ends of its route to energize it with a polarity opposite to that polarity of energization with which it was intially energized so long as it is maintained energized by its said stick circuit means; and means for interlocking said route relays so as to allow only one among any of the conflicting routes to be energized at the same time.

13. In a switch and signal control system for railroads, a track layout having power-operated track switches for setting up'diierent routes between entrance and exit signal locations, selfrestoring manually operable control buttons associated with said signal locations, one for each of said signals for designating such signal location as an entrance or an exit point, route establishing means rendered active in response to the momentary operation of a manual control device to designate an entrance signal location followed by the momentary operation of a manual control device to designate an exit signal location to cause the power operation of the required switches to establish a route between such signal locations and also to prevent the response of said route establishing means to manual control buttons for the entrance and exit ends of any route that would conflict with such established route, and means for maintaining said route establishing means active with respect to an established route until a train has passed through such established route.

14. In a switch and signal control system for railroads, a track layout having power operated track switches for setting up different routesbetween entrance and exit signal locations, selfrestoring manuallyoperable control buttons associated with said signal locations one for each of said signals for designating the corresponding signal location as an entrance or an exit point, manually operable stop contacts one associated with each of said signal locations, route establishing means rendered active in response to the momentary operation of a control button to designate an entrance signal location followed by the momentary operation 'of a control button to designate an exit signal location to cause the power operation of the required switches to establish a route between such signal locations and to clear the signal at the entrance to such route, said route establishing means also acting to prevent the response of said route establishing means to manual control buttons for the entrance and exit ends of any route that would conflict with such established route, holding circuit means for maintaining said route establishing means active for an established route independent of the restoration of said control buttons and in accordance with the condition of occupancy of such route to thereby prevent the response of said route establishing means to control buttons for a conflicting route while such route is established and is occupied by a train, and means for restoring any given signal to stop irrespective of said holding circuit means upon the opening of its associated manually operable stop contact.

15. In a switch and signal control system for railroads; a track layout having power operated track switches for setting up different routes between signal locations constituting the entrance and/or exit ends of such routes; manually operable control devices associated with said signal locations, each for designating its signal location as the entrance or exit end of a route; route establishing means rendered active, only in response to the operation of a manually operable control device to designate any given signal location as the exit end of a route within a limited time after the operation of a manually operable control device to designate a signal location as the entrance end of a route, to cause the power operation of the required track switches to establish a route between the designated entrance and exit signal locations, said route establishing means being conditioned while thus rendered active so as to be unresponsive to the operation of manually operable control. vdevices for the entrance and exit ends of any route that conflicts with such an established route and circuit means controlled by said route establishing means for clearing the signal at that end of an established route designated as the entrance end of such route.

16. In a switch and signal control system for railroads; a track layout having power-operated track switches for'setting up different routes between entrance and exit signal locations; selfrestoring manually operable control buttons associated with said signal locations, one for each of said signals for designating such signal location as an entrance or an exit point; route establishing means rendered active only in response to the operation of a manually operable control button to designate an eXit signal location within a limited time after the operation of a manually operable control button to designate an entrance signal location tocause the power operation of the required track switches to establish a route between such designated signal locations and clear the signal at the entrance to that route, said route establishing means being conditioned while thus rendered active so as to be unresponsive to the operation of control buttons for the entrance and eXit ends of any route that conflicts with such established route; and track circuit controlled means for maintaining said route establishing means active with respect to an established route independently of the restoration of said manually operable control buttons for the entrance and eXit ends of that route.

17. In a switch and signal control system for railroads; a track layout having power-operated track switches forl setting up different routes between signal locations constituting the entrance and/or exit ends of such routes; manually operable control devices associated with said signal locations, each for designating its signal location as the entrance or exit end of a route, timing means rendered active for only a predetermined time by the operation of a manually operable control device to designate its signal location as the entrance end of a route; route establishing means rendered active to control the power operation of said track switches to establish any given route and clear a signal governing traiic thereover in response to the operation of a manually operable control device to designate the eXit end of said given route following the operation of a manually operable control device to designate the entrance end of that route only if said timing means is then active, said route establishing means being unresponsive to the operation of manually operable control devices for the entrance and exit 'ends ofA routes which conict with kan established route; and track circuit controlled means for maintaining said route establishing means active for a route once established independently of 'said timing means; whereby any one operation of a manually controlled device to designate a signal location as the entrance end of a route can control said route establishing means only during a limited time.

18. In a switch and signal control system for railroads a track layout having power-operated track switches for setting up different routes between signal locations constituting the entrance and/orexit ends of such routes; manually operable control devices associated with said signal locations, each for designating its signal location as the entrance or exit end of a route; normally closed manually operable stop' contacts associated with said signals, one for each signal; timing means rendered active to measure a predetermined time upon the operation of a manually operable control device to designate its signal location as the entrance end of a route; route establishing means rendered active to control the power operation of said track switches to establish any given route and clear a signal governing traffic thereover in response to the operation of a manually operable control device to designate the eXit end of said given route following the operation of a manually operable control device to designate the entrance end of that route only if said timing means is then active, said route establishing means being unresponsive to the operation of manually operable control devices for the entrance and eXit ends of routes which conict with an established route; and circuit means for maintaining said route establishing means active for a route established dependent upon the closed condition of said stop contact for the signal at the entrance to such established route Vindependently of said timing means.

, 19. In a switch and signal control system for railroads, a track layout having power operated track switches for setting up different routes between entrance and exit signal locations; selfrestoring manually operable control buttons associated with said signal locations, one for each of said signals for designating such signal location as the entrance or exit end of a route; a slow acting relay associated with each of said control buttons and controlled thereby to measure a predetermined time following each operation of such control button; route establishing means'for governing the power operation of said track switches to set up any given route and clear the signal at the entrance thereto when rendered active for that given route; circuit means'including contacts of said slow acting relays for rendering said route establishing means active withrespect to any given route only upon the operation of the control button for the exit end of such route within said predetermined time following the operation of the control button for the entrance end Y of that route; and track circuit controlled circuit means acting on said route establishing means for maintaining any given established route active dependent upon trahie conditions.

20. In a switch and signal control system for railroads; a track layout having power-operated track switches for setting up diiTerent routes between signal locations constituting the entrance and/or exit ends of such routes; manually operable contacts associated with said signals; each signal having controlling contacts and stop contacts; timing means rendered active by the manual operation of the control contacts for any given signal location; route establishing means for governing the power operation of said track switches to set up any given route and clear the signal at the entrance thereto when rendered active for that given route; circuit means including contacts of said timing means for rendering said route establishing means active with respect to any given route only upon the operation of the control contact for the exit end of such route within said predetermined time following the operation of theY control Contact for the entrance end of that route; and holding circuit means efiective to maintain said route establishing means active with respect to any given established route dependent upon said stop contact for the signal at the entrance to such route, said holding circuit means also being eiective to maintain said route establishing means active with respect to any given established route while that route is occupied by a train; whereby any route which has been established can be manually returned to stop, and whereby a route occupied by ar train prevents said route establishing means from responding to the operation of control contacts for the entrance and eXit ends of routes in conflict with such established route.

STUART J. MACKEY. 

